Display device and method for controlling display image

ABSTRACT

A flexible display device and a method for controlling a display image are disclosed. In one aspect, the flexible display device includes a first display which has a flat shape and a second display which is disposed on either side of the first display and has a curved surface bent at a boundary between the first and second displays. The display further includes a controller which controls a screen of at least one of the first and second displays according to a user touch and/or a battery capacity.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This application claims the benefit of Korean Patent Application No.10-2012-0120616, filed on Oct. 29, 2012, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein in itsentirety by reference.

BACKGROUND

1. Field

The described technology generally relates to a display device and amethod for controlling a display image.

2. Description of the Related Technology

Flexible displays have been recently spotlighted as a new displaytechnology. A flexible display is generally realized on a thin andbendable substrate which is formed of plastic or the like. Therefore,even if the flexible display is folded or rolled like a paper sheet, theflexible display is not damaged. A liquid crystal display (LCD) and anorganic light-emitting display (OLED) each including a thin filmtransistor (TFT) are currently used to realize a flexible display.

SUMMARY

One inventive aspect is a user interface and a method for effectivelycontrolling a display image of a flexible display device.

Another aspect is a display device including: a first display which hasa flat shape; a second display which is disposed on either side of thefirst display and has a curved surface bent at a boundary between thefirst and second displays; and a controller which controls a screen ofat least one of the first and second displays according to a touch of auser or a capacity of a battery.

The controller may detect a touch characteristic according to acombination of touch inputs of the first and second displays andgenerate an event according to the touch characteristic. If the touchcharacteristic includes a drag of the second display, the controller maygenerate the event in response to the drag. If the touch characteristicis consecutive drags of the first and second displays in an imageselecting mode, the controller may zoom in or out an image, which isscrolled according to the drag of the first display, according to thedrag of the second display. If the touch characteristic is the drag ofthe second display in a text input mode, the controller may scroll andoutput a text according to an up and down or left and right drag of thesecond display. The controller may substantially simultaneously generatethe event and provide feedback to the user in response to the drag ofthe second display. The feedback may be a vibration or a sound.

The controller may control the screen of the at least one of the firstand second displays to be turned on or off according to a left capacityof the battery. The controller may estimate a left time of the batterybased on the left capacity of the battery and, if the left time isshorter than or equal to a reference time, may change a mode to a powercontrol driving mode which is to turn off at least part of the screen ofthe at least one of the first and second displays. The left time may becalculated based on a current consumption and a temperature of thebattery. The controller may measure a voltage of the battery and, if thevoltage of the battery is lower than or equal to a reference voltage,may change a mode to a power control driving mode which is to turn offat least part of the screen of the at least one of the first and seconddisplays.

Another aspect is a method for controlling a display image of a displaydevice including a first display which has a flat shape and a seconddisplay which is disposed on either side of the first display and has acurved surface bent at a boundary between the first and second displays.The method may include: controlling a screen of at least one of thefirst and second displays based on a touch of a user or a capacity of abattery.

The control of the screen may include: receiving touch inputs of thefirst and second displays; detecting a touch characteristic according toa combination of the touch inputs; and generating an event according tothe touch characteristic. The generation of the event may include: ifthe touch characteristic includes a drag of the second display,generating the event in response to the drag. The generation of theevent may include: if the touch characteristic is a drag of the firstdisplay in an image selecting mode, scrolling an image according to thedrag of the first display; and if the touch characteristic is detectedas a drag of the second display subsequent to the drag of the firstdisplay, zooming in or out the scrolled image according to the drag ofthe second display. The generation of the event may include: if thetouch characteristic is the drag of the second display in a text inputmode, scrolling and outputting a text according to an up and down orleft and right drag of the second display. The method may furtherinclude: substantially simultaneously generating the event and providinga feedback to the user.

The control of the screen may include: estimating a left time of thebattery based on a left capacity of the battery; and if the left time isshorter than or equal to a reference time, changing a mode to a powercontrol driving mode which is to turn off at least part of the screen ofthe at least one of the first and second displays. The estimation of theleft time may include: estimating the left time based on a currentconsumption and a temperature of the battery. The control of the screenmay include: measuring the voltage of the battery; and if the voltage ofthe battery is lower than or equal to a reference voltage, changing amode to a power control driving mode which is to turn off at least partof the screen of the at least one of the first and second displays.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view illustrating a flexible displaypanel according to an exemplary embodiment.

FIG. 2 is a plan view of the flexible display panel.

FIG. 3 is a schematic perspective view illustrating first and seconddisplays of the flexible display panel which display image signals inputfrom different image signal input units, according to an exemplaryembodiment.

FIGS. 4A through 4C are schematic views illustrating informationprovided by the second display of FIG. 3, according to an exemplaryembodiment.

FIG. 5 is a schematic view illustrating a mounting type for combining aflexible display panel into a housing according to an exemplaryembodiment.

FIG. 6 is a schematic perspective view illustrating a flexible displaypanel according to another exemplary embodiment.

FIG. 7 is a schematic block diagram illustrating a structure of adisplay device in which a flexible display panel is installed, accordingto an exemplary embodiment.

FIGS. 8 and 9 are schematic views illustrating a touch input of adisplay device in which a flexible display panel is installed, accordingto an exemplary embodiment.

FIG. 10 is a flowchart illustrating a method for controlling a displayimage of a display device including a flexible display panel accordingto an exemplary embodiment.

FIG. 11 is a flowchart schematically illustrating a method for inputtingcharacters according to an exemplary embodiment.

FIGS. 12 and 13 are views illustrating an example of the method of FIG.11.

FIGS. 14 and 15 are flowcharts illustrating a method for controlling adisplay image of a display device according to another exemplaryembodiment.

FIGS. 16A through 16G are views illustrating various types of screencontrolling patterns according to various exemplary embodiments.

DETAILED DESCRIPTION

Accordingly, while example embodiments are capable of variousmodifications and alternative forms, embodiments thereof are shown byway of example in the drawings and will herein be described in detail.It should be understood, however, that there is no intent to limitexample embodiments to the particular forms disclosed, but on thecontrary, example embodiments are to cover all modifications,equivalents, and alternatives thereof. Like numbers refer to likeelements throughout the description of the figures.

It will be understood that, although the terms, ‘first’, ‘second’, etc.may be used herein to describe various elements, these elements shouldnot be limited by these terms. These terms are only used to distinguishone element from another.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of exampleembodiments. As used herein, the singular forms “a,” “an,” and “the,”are intended to include the plural forms as well, unless the contextclearly indicates otherwise. It will be further understood that theterms “comprises,” “comprising,” “includes,” and/or “including,” whenused herein, specify the presence of stated features, integers, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof.

In the drawings, the thicknesses of layers and regions may beexaggerated for clarity. In the drawings, the thicknesses of layers andregions may be exaggerated for clarity. It will also be understood thatwhen a layer is referred to as being “on” another layer or substrate, itcan be directly on the other layer or substrate, or intervening layersmay also be present.

Hereinafter, embodiments will be described in detail with reference tothe attached drawings.

FIG. 1 is a schematic perspective view illustrating a flexible displaypanel 100 according to an exemplary embodiment. FIG. 2 is a plan view ofthe flexible display panel 100.

The flexible display panel 100 according to the present exemplaryembodiment includes a first display D1 and a second display D2 (D21 andD22) disposed on either side of the first display D1. A non-display areaNA is disposed at edges of the first and second displays D1 and D2.

Referring to FIGS. 1 and 2, the first display D1 is substantially flatand may be a main display screen of the flexible display panel 100.

The second display D2 is formed of a curved surface having apredetermined radius curvature. The second display D2 extends from thefirst display D1 to be connected to the first display D1. Since thesecond display D2 has the curved surface which is bent at a boundarybetween the first and second displays D1 and D2, a display screen of theflexible display device 100 is not limited to the first display D1 butextends the display screen up to the second display D2 for a user. Inother words, a whole display screen may increase due to the seconddisplay D2. The second display D2 may be a sub-display screen of theflexible display panel 100.

If the flexible display panel 100 is installed in a small-size displaydevice grabbed by a hand like a cellular phone or a personal digitalassistant (PDA), the second display D2 forms the curve surface.Therefore, a grip sensitivity may increase, and an aesthetic sense mayincrease due to the curved surface.

The non-display area NA is disposed at the edges of the first and seconddisplays D1 and D2. The non-display area NA may be folded inside not tobe seen by the user.

The first and second displays D1 and D2 may include a plurality ofpixels having various types of display devices (not shown), such as atleast one or more organic light-emitting displays, liquid crystaldisplays (LCDs), electrophoretic devices, etc., and at least one or morethin film transistors (TFTs), and storage capacitors, etc.

The first and second displays D1 and D2 may display an image signalinput from an image signal input unit. Therefore, all of the first andsecond displays D1 and D2 may function as one display screen.

However, the present invention is not limited thereto, and thus thefirst and second displays D1 and D2 may independently display the imagesignals input from the different image signal input units.

FIG. 3 is a schematic perspective view illustrating the first and seconddisplays D1 and D2 of the flexible display panel 100 which display imagesignals input from different image signal input units, according to anexemplary embodiment. FIGS. 4A through 4C are schematic viewsillustrating information provided by the second display D2 of FIG. 3,according to an exemplary embodiment.

In the present exemplary embodiment, certain information may be providedto a user by using the second display D2, which is a bent side area ofthe flexible display panel 100, without damaging or stopping contentsprovided from the first display D1 which is a main display.

Referring to FIGS. 3 and 4A through 4C, the first display D1 mayfunction as a main screen, and the second display D2 may function as subscreens such as various types of icons I.

As shown in FIG. 4A, the second display D2 may provide a user interface(UI) function which is to display a path or a depth of a folder. Whenthe user performs a file management job such as a file search, a filecopy, a file move, or the like, the second display D2 may display a pathof a whole folder which is currently located.

Alternatively, as shown in FIG. 4B, the second display D2 may provide anintuitive UI function which is to display a multi-tasking bar. Thesecond display D2 may provide a task progress state display and allowthe user to directly select a task.

As shown in FIG. 4C, the second display D2 may provide a UI functionwhich is to display certain information including, but not limited to,accounting information, network information, and so on. When the firstdisplay D1 provides a service and an application such as a movingpicture, an Internet search, etc., the second display D2 may provide theuser with accounting and network use information in real time withoutdamaging or stopping information provided from the first display D1.

FIG. 5 is a view illustrating a mounting type for combining a flexibledisplay panel into a housing according to an exemplary embodiment.

The flexible display panel 100 whose curved surface is maintained byvarious types of support means may be integrated into various types ofdisplay devices. In some embodiments, examples of the display devicesinclude a television (TV), a cellular phone, a smart phone, a notebookcomputer, a monitor, a digital broadcasting terminal, a PDA, a portablemultimedia player (PMP), a navigation, etc.

Referring to FIG. 5, the flexible display panel 100 is combined into adisplay device. The display device includes a frame or housing 160 whichprotects and supports the display device. In the present exemplaryembodiment, the flexible display panel 100 is bent so that the seconddisplay D2 forms the curved surface and is attached on an upper surfaceof a front case 161 of the housing 160. Also, the non-display area NA ofthe flexible display panel 100 is folded and placed in an opening 163formed between the front case 161 and a lower case 162 of the housing160. Therefore, the non-display area NA may be prevented from being seenoutside the display device.

A touch panel 140 and a window 150 which is a transparent protectivewindow are installed on an upper surface of a side of the flexibledisplay panel 100 on which an image is realized. The touch panel 140 mayinclude first and second touch areas respectively corresponding to thefirst and second displays D1 and D2. The touch panel 140 may adoptvarious types of touch methods such as a capacitive method, a resistivemethod, etc. The window 150 may protect the flexible display panel 100from external shocks or scratches and operate as a support mean whichmaintains a shape of the flexible display panel 100.

FIG. 6 is a schematic perspective view illustrating a flexible displaypanel 200 according to another exemplary embodiment.

The flexible display panel 200 of FIG. 6 is different from the flexibledisplay panel 100 of FIG. 1 in that a second display D2 is positionedonly on a side of a first display D1.

The flexible display panel 200 includes the first display D1 and thesecond display D2 which extends from the side of the first display D1. Anon-display area NA is disposed at edges of the first and seconddisplays D1 and D2. The first display D1 may be a main display screen ofthe flexible display panel 200. The second display D2 may be a subdisplay screen of the flexible display panel 200.

The first and second displays D1 and D2 may include a plurality ofpixels having various types of display devices (not shown), such as atleast one or more organic light-emitting displays, liquid crystaldisplays (LCDs), electrophoretic devices, etc., and at least one or morethin film transistors (TFTs), and storage capacitors, etc.

Although not shown in FIG. 6, the flexible display panel 200 and a touchpanel corresponding to the shape of the flexible display panel 200 maybe combined into a display device.

The second display D2 forms the curved surface in the previous exemplaryembodiment. However, the present exemplary embodiment is not limitedthereto, and a boundary area between the first and second displays D1and D2 may form a curved surface, and the second display D2 may have aflat shape.

FIG. 7 is a schematic block diagram illustrating a structure of thedisplay device 10 in which a flexible display panel is installed,according to an exemplary embodiment.

Referring to FIG. 7, the display device 10 includes a display 20, a userfeedback provider 30, a power supply unit 40, and a controller 50.

The display 20 displays an image which is captured by a camera (notshown) installed in the display device 10 or is received from anexternal source by wire or wireless, a UI, or a graphic user interface(GUI). The display 20 may display various types of state information,numbers, characters, images, etc., occurring when the display device 10operates. The display 20 may be constituted as the flexible displaypanel 100, with which a touch panel forms a single body, to be used asan output unit and/or an input unit.

The display 20 includes a first display D1 and a second display D2 whichis disposed on both sides of the first display D1 and is bent at aboundary between the first and second display D1 and D2. The display 20includes a touch panel to receive a touch input.

The user feedback provider 30 generates various types of tactile effectsfelt by a user like a vibration and acoustic effects such as soundsunder control of the controller 50.

The power supply unit 40 receives an external and/or internal powersource to supply power for operations of elements of the display device10. The power supply unit 40 may include a rechargeable battery. Thepower supply unit 40 may measure main parameters of the rechargeablebattery such as charging, discharging, and a temperature. The powersupply unit 40 controls power supplies to the first and second displaysD1 and D2 under control of the controller 50.

The controller 50 controls an overall operation of the display device10. For example, the controller 50 performs related controls andprocessing for a voice call, a data communication, a video telephony,etc. The controller 50 may control a screen of at least one of the firstand second displays D1 and D2 according to a touch of the user or acapacity of the battery.

The controller 50 may control the screen of the at least one of thefirst and second displays D1 and D2 according to the touch of the user.If the display 20 receives touch inputs, the controller 50 detects atouch characteristic according to a combination of the touch inputs ofthe first and second displays D1 and D2 and generates different eventsaccording to the touch characteristic. The touch characteristic may be atouch position, the number of touches, a drag, or the like in thepresent invention but is not limited thereto. Therefore, various typesof touch characteristics may be defined. Here, a touch refers to a statein which a finger of the user or a stylus pen contacts the display 20.Also, a drag refers to an operation which is to move a touch point whenkeeping a touch on the display 20.

The controller 50 may also control the screen of the at least one of thefirst and second displays D1 and D2 according to the capacity of thebattery. The controller 50 may estimate a current voltage of the batteryor a left time of the battery and control a screen of the display 20.Therefore, the controller 50 may perform a function of controlling powerof the display device 10 in the present exemplary embodiment.

FIGS. 8 and 9 are schematic views illustrating touch inputs of thedisplay device 10 including a flexible display panel, according to anexemplary embodiment.

The second display D2 of the present exemplary embodiment may provide afunction such as a virtual jog dial or knob. Therefore, as shown in FIG.8, the user may drag the second display D2 from a left side to a rightside (or from a right side to a left side) like the jog dial or knob.For example, the user may perform a drag in a direction from the firstdisplay D1 to the second display D2 with a finger (e.g., a thumb).

Referring to FIG. 9, the user may drag the second display D2 from top tobottom (or from bottom to top). For example, the user may drag thesecond display D2 from the top to the bottom (or from bottom to top)with the finger (e.g., the thumb).

In the present exemplary embodiment, a 2-dimensional (2D) coordinate (x,y) obtained by a 2D touch of the first or second display D1 or D2 anddrag information of the second display D2 may be received and thenextend into a 3-dimensional (3D) coordinate (x, y, z) or (x, y, depth orzoom) by using the 2D coordinate and the drag information.

FIG. 10 is a flowchart illustrating a method for controlling a displayimage of a display device including a flexible display panel accordingto an exemplary embodiment. The method of the present exemplaryembodiment refers to a method for controlling a screen of the displaydevice based on a touch of a user. Depending on the embodiment,additional operations may be added, others removed, or the order of theoperations may change in FIG. 11. This applies to the embodiments ofFIGS. 11, 14 and 15.

In operation S101, the controller 50 receives touch inputs from thedisplay 20. In operation S103, the controller 50 combines the touchinputs of the first and second displays D1 and D2 in order and detects atouch characteristic according to the combination of the touch inputs.

In operation S105, the controller 50 determines whether the touch inputsare 2D touches or 3D touches, based on the touch characteristic. Thecontroller 50 may determine a touch type in consideration of whether thetouch inputs are a drag of the second display D2 subsequent to a 2Dtouch operation or which area a drag has occurred in. If the detectedtouch characteristic includes a left and right or up and down drag ofthe second display D2, the controller 50 may determine the touch type asa 3D touch. In some embodiments, the 3D touch refers to a touchincluding a left and right drag operation of the second display D2subsequent to a 2D touch of the first display D1 or a drag of the seconddisplay D2 such as a single up and down or left and right drag operationof the second display D2. Here, the 2D touch refers to a touch such as aone-time touch of the first or second display D1 or D2, consecutive twotime touches, or a drag of the first display D1.

If it is determined in operation S105 that the touch inputs are the 2Dtouch, the controller 50 performs an operation corresponding to eachtouch characteristic. For example, if the touch inputs are a one-timetouch of the first or second display D1 or D2, the controller 50 mayperform a click function. If the touch inputs are the two time touch,the controller 50 may perform a double click function. If the touchinputs are the drag of the first display D1, the controller 50 mayperform a scroll function. Here, a scroll means that a content displayedon a screen of the display 20 move up and down or from side to side.

If the touch inputs are the 3D touch, the controller 50 controls thescreen of the display 20 and provides a feedback to a user according toa display mode type in operation S109. For example, if a touchcharacteristic in which the drag of the first display D1 and then theleft and right drag of the second display D2 are consecutive when ascrollable image is displayed on the first display D1, the controller 50may scroll the image and zoom in or out an image selected by the scroll.A zoom magnification of the image may be adjusted according to a dragtime or a touch pressure of the second display D2. Here, the controller50 may transmit a control signal to the user feedback provider 30 sothat the user feedback provider 30 may provide the user with a vibrationor a sound which is a haptic function at the same time as a zoomfunction is performed.

FIG. 11 is a flowchart schematically illustrating a method for inputtingcharacters according to an exemplary embodiment. FIGS. 12 and 13 areviews illustrating an example of the method of FIG. 11.

When a display mode of the display 20 is a character input mode, a 3Dtouch is sensed in operation S201. In operation S203, the controller 50outputs a character search UI to the first display D1.

If a user left and right drags the second display D2 as shown in FIG.12, the controller 50 performs a scroll operation which is to rotate aconsonant through the character search UI in operation S205. If the userup and down drags the second display D2 as shown in FIG. 13, thecontroller 50 performs a scroll operation which is to rotate a vowelthrough the character search UI in operation S207. However, the presentinvention is not limited thereto, and the controller 50 may perform avowel scroll operation through a left and right drag and perform aconsonant scroll operation through an up and down drag.

In operation S209, the controller 50 provides the user with a feedbackas a vibration or a sound through the user feedback provider 30 at atime when scrolling a consonant or a vowel or a time when selecting theconsonant or the vowel.

An example of a character input is described in the above-describedexemplary embodiment, but an input of a number or a symbol may beperformed through a scroll operation by a drag of the second display D2.

In the present exemplary embodiment, the user may hold the displaydevice 10 such as a portable terminal with a hand to touch the seconddisplay D2 with only a thumb in order to perform a scroll operation anda character input of the display device 10. Also, since all of left andright sides of the display device 10 are used, this may be appliedregardless of a left or right hand of the user.

FIGS. 14 and 15 are flowcharts illustrating a method for controlling adisplay image of a display device according to another exemplaryembodiment. FIGS. 16A through 16G are views illustrating screencontrolling patterns according to various exemplary embodiments.

The method of the present exemplary embodiment is a method forcontrolling a screen of the display device based on a capacity of abattery. In other words, contents are displayed on the whole display 20,i.e. the first and second displays D1 and D2, in a normal state of thebattery having a sufficient left time and a sufficient voltage. However,if the voltage or the left time becomes lower than a level pre-definedby a manufacturer or a user, a power control driving mode may beapplied.

In operation S301, the controller 50 estimates the left time. Inoperation S302, a determination is made as to whether the estimated lefttime is shorter than or equal to a reference time. The reference timerefers to a minimum left time preset by the user or the manufacturer.The left time T_left may be calculated by using a current consumptionand a temperature of the battery. The current consumption refers to atotal amount of current (I) currently (or at a measurement time)consumed in a user terminal. The temperature of the battery refers to acurrent temperature of the battery (that is, a temperature of thebattery at the measurement time). Efficiency of the battery depends onthe temperature, and thus the temperature of the battery is additionallyconsidered. The left time T_left may be calculated by Equation below;

${T\_ left} = {\frac{\text{TotalBatteryCapacity}}{{Avr\_ Curr}{\_ con}{\_ T}} \times \frac{BatteryEfficiency}{{Var\_ Curr}{\_ Con}{\_ T}}}$wherein Avr_Curr_con_T denotes an average of current consumptions for apredetermined time T, and Var_Curr_con_T denotes a dispersion of thecurrent consumptions. If the left time is estimated in consideration ofonly the average of the current consumptions, an error is great.Therefore, variations in the current consumptions are additionallyconsidered. The efficiency of the battery may be calculated from adatabase (DB) including a discharging characteristic of the batterydepending on the temperature. The DB may be pre-stored in a storagemeans such as a memory.

In operation S303, the controller 50 measures a current voltage of thebattery. In operation S304, the controller 50 determines whether thecurrent voltage of the battery is lower than or equal to a referencevoltage. The reference voltage is a minimum voltage preset by a user ora manufacturer. The reference voltage may be changed by the user.

If the left time is longer than or substantially equal to the referencetime, and the current voltage of the battery is higher than orsubstantially equal to the reference voltage, the controller 50 changesa current mode to a normal driving mode in operation S305. Therefore,contents are provided to the first and second displays D1 and D2 asshown in FIG. 16A.

If the left time is shorter than or substantially equal to the referencetime, and the current voltage of the battery is lower than orsubstantially equal to the reference voltage, the controller 50 changesthe current mode to a power control driving mode in operation S306. Thepower supply unit 40 may reduce or stop a supply of power to at leastone of the first and second displays D1 and D2. Therefore, outputting ofcontents on a screen of at least one of the first and second displays D1and D2 may be limited.

In operation S307, the controller 50 selects a screen controllingpattern of the first and second displays D1 and D2 in the power controldriving mode. The controller 50 may control the power supply unit 40 tosupply power to the display 20 according to the selected screencontrolling pattern.

In operation S308, the controller 50 controls a screen according to theselected screen control pattern. Therefore, only the second display D2may display contents as shown in FIG. 16B, only the first display D1 maydisplay a content as shown in FIG. 16C, or the first display D1 and onlysome of the second display D2 may display a content as shown in FIG.16G. The content of the first display D1 may be reduced to be displayedin an area of the first display D1 as shown in FIGS. 16D and 16E.Alternatively, not the content but a message related to a left capacityof the battery may be displayed on the first and second displays D1 andD2 as shown in FIG. 16F. Screen controlling patterns may be allocatedaccording to the left capacity (or a left time or voltage), and thecontroller 50 may select a screen controlling pattern according to theleft capacity of the battery to control the screen.

A power control using only a voltage of a battery may be performed byusing a simple structure, but a power control according to a use patternor environment of a user may be impossible. According to an exemplaryembodiment, the user may perform a power control according to a lefttime estimation, which is based on data a current consumption used bythe user at a current time and a previous consumption and informationabout the battery, in order to enable the power control according to theuse pattern or environment of the user. Also, a power control method forproviding contents to some area of the display 20 may be applied toeffectively extend a left time of the battery in a low voltagesituation.

According to at least one of the disclosed embodiments, a screen may becontrolled by a touch of a bent side of a flexible display device toincrease uses of a user. Also, the screen may be controlled according toa capacity of a battery of the flexible display device to improveefficiency of power uses.

While the above embodiments have been described with reference to theaccompanying drawings, it will be understood by those of ordinary skillin the art that various changes in form and details may be made thereinwithout departing from the spirit and scope of the present invention asdefined by the following claims.

What is claimed is:
 1. A display device comprising: a first displayhaving a substantially flat shape, wherein the first display comprisestwo opposing sides; a second display disposed on at least one of the twosides of the first display and having a curved surface bent at aboundary between the first and second displays, wherein the seconddisplay is surrounded by a non-display portion that is not visible fromoutside the display device; and a controller configured to control ascreen of at least one of the first and second displays based on a usertouch of the display device, wherein the controller is configured todetect a touch characteristic according to the a combination of touchinputs of the first and second displays, wherein the controller isconfigured to generate an event corresponding to the touchcharacteristic and provide feedback to the user, if the touch inputscomprise a drag of the second display having the curved surface, andwherein if the touch characteristic is the drag of the second display ina text input mode, the controller is further configured to output acharacter search UI to the first display and rotate vowels in an up anddown direction through the character search UI according to an up anddown drag of the second display and rotate consonants in a left andright direction through the character search UI according to a left andright drag of the second display.
 2. The display device of claim 1,wherein the feedback comprises at least one of a vibration and a sound.3. The display device of claim 1, wherein the controller is furtherconfigured to control the screen of the at least one display of thefirst and second displays to be turned on or off by reducing or stoppinga supply of power to at least one of the first and second displaysaccording to remaining battery capacity.
 4. The display device of claim3, wherein the controller is further configured to estimate remainingbattery lifetime based at least partially on remaining battery capacityand wherein, if the remaining battery lifetime is shorter than orsubstantially equal to a reference time, the controller is furtherconfigured to change a mode to a power control driving mode which is toturn off at least part of the screen of the at least one display.
 5. Thedisplay device of claim 4, wherein the controller is further configuredto calculate the remaining battery lifetime based at least partially oncurrent consumption and temperature of the a battery.
 6. The displaydevice of claim 3, wherein the controller is further configured tomeasure battery voltage and, wherein, if the measured voltage is lowerthan or substantially equal to a reference voltage, the controller isfurther configured to change a mode to a power control driving modewhich is to turn off at least part of the screen of the at least onedisplay.
 7. A method for controlling a display image of a displaydevice, the method comprising: providing a display device thatcomprises 1) a first display having a substantially flat shape, whereinthe first display comprises two opposing sides and 2) a second displaydisposed on at least one of the two sides of the first display andhaving a curved surface bent at a boundary between the first and seconddisplays, wherein the second display is surrounded by a non-displayportion that is not visible from outside the display device; andcontrolling a screen of at least one of the first and second displaysbased on a user touch of the display device, wherein the controllingcomprises: receiving touch inputs of the first and second displays;detecting a touch characteristic according to the a combination of thetouch inputs; and generating an event corresponding to the touchcharacteristic and providing feedback to the user, if the touch inputscomprise a drag of the second display having the curved surface, andwherein the generating comprises: if the touch characteristic is thedrag of the second display in a text input mode, outputting a charactersearch UI to the first display and rotating vowels in an up and downdirection through the character search UI according to an up and downdrag of the second display and rotating consonants in a left and rightdirection through the character search UI according to a left and rightdrag of the second display.
 8. The method of claim 7, wherein thegenerating comprises: if the touch characteristic is a drag of the firstdisplay in an image selecting mode, scrolling an image according to thedrag of the first display; and if the touch characteristic is detectedas a drag of the second display subsequent to the drag of the firstdisplay, zooming in or out the scrolled image according to the drag ofthe second display.
 9. The method of claim 7, wherein the generatingcomprises: if the touch characteristic is the drag of the second displayin a text input mode, scrolling and outputting a character search UI tothe first display and rotating vowels or consonants through thecharacter search UI according to an up and down or left and right dragof the second display.
 10. The method of claim 7, wherein thecontrolling further comprises: estimating remaining battery lifetimebased at least partially on remaining battery capacity; and if theremaining lifetime is shorter than or substantially equal to a referencetime, changing a mode to a power control driving mode which is to turnoff at least part of the screen of the at least one display of the firstand second displays by reducing or stopping a supply of power to atleast one of the first and second displays.
 11. The method of claim 10,wherein the estimating comprises: estimating battery lifetime based oncurrent consumption and battery temperature.
 12. The method of claim 7,wherein the controlling comprises: measuring battery voltage; and if themeasured battery voltage is lower than or substantially equal to areference voltage, changing a mode to a power control driving mode whichis to turn off at least part of the screen of the at least one displayof the first and second displays by reducing or stopping a supply ofpower to at least one of the first and second displays.
 13. A displaydevice comprising: a first display having a substantially flat shape,wherein the first display comprises two opposing sides; a second displaydisposed on at least one of the two sides of the first display andhaving a curved surface bent at a boundary between the first and seconddisplays, wherein a non-display portion surrounds the second display; acontroller configured to control a screen of at least one of the firstand second displays based at least partially on a user touch and/or abattery capacity of the display device; and a housing supporting thefirst and second displays, wherein the housing comprises an upper casecontacting the first and second displays and a lower case facing theupper case, and wherein the non-display portion is inwardly bent fromthe second display such that the second display and the bent portion atleast partially surround the upper case, wherein the controller isconfigured to detect a touch characteristic according to the acombination of touch inputs of the first and second displays, whereinthe controller is configured to generate an event corresponding to thetouch characteristic and provide feedback to the user, if the touchinputs comprise a drag of the second display having the curved surface,and wherein if the touch characteristic is the drag of the seconddisplay in a text input mode, the controller is further configured tooutput a character search UI to the first display and rotate vowels orconsonants through the character search UI according to an up and downor left and right drag of the second display.
 14. The display device ofclaim 13, wherein the non-display portion is not visible.
 15. Thedisplay device of claim 13, wherein the controller is further configuredto control the screen of at least one display of the first and seconddisplays to be turned on or off by reducing or stopping a supply ofpower to at least one of the first and second displays according toremaining battery capacity.
 16. The display device of claim 13, whereinif the touch characteristic is consecutive drags of the first and seconddisplays in an image selecting mode, the controller is furtherconfigured to zoom in or out an image, which is scrolled according tothe drag of the first display, according to the drag of the seconddisplay.
 17. The display device of claim 15, wherein the controller isfurther configured to estimate remaining battery lifetime based at leastpartially on remaining battery capacity and wherein, if the remainingbattery lifetime is shorter than or substantially equal to a referencetime, the controller is further configured to change a mode to a powercontrol driving mode which is to turn off at least part of the screen ofthe at least one display.
 18. The display device of claim 15, whereinthe controller is further configured to measure battery voltage and,wherein, if the measured voltage is lower than or substantially equal toa reference voltage, the controller is further configured to change amode to a power control driving mode which is to turn off at least partof the screen of the at least one display.
 19. The display device ofclaim 1, further comprising a housing supporting the first and seconddisplays, wherein the housing comprises an upper case contacting thefirst and second displays and a lower case facing the upper case, andwherein a non-display portion surrounds the second display and thenon-display portion is inwardly bent from the second display such thatthe second display and the bent portion at least partially surround theupper case.
 20. The display device of claim 17, wherein an opening isformed only between edges of the upper and lower cases, and wherein thenon-display portion is formed only in and adjacent to the opening. 21.The display device of claim 1, further comprising a touch panelcorresponding to the first and second displays.